Dental or surgical chair.



G. HOLTZ.

DENTAL 0R SURGICAL CHAIR.

APPLICATION FILED FEB.29,1908.

Patented Dot. 5, 1909.

I I I M I l I 65 I 71 2/ 1 39 E Q (5 1 69 3 i 011 G. HOLTZ. DENTAL 0RSURGICAL CHAIR.

APPLICATION FILED FEB.29,1908.

Patented Oct. 5, 1.909.

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DENTAL 0R SURGICAL GHAIE.

Specification of Letters Patent.

Patented Oct. 5, race.

Application filed. February as, was. Serial no. traces.

To all whom 'it may concern:

Be it known that I, GUSTAV HOLTZ, a citizen of the United States,residing at Gouldshero, in the county of Wayne and State ofPennsylvania, have invented a new and useful Dental or Surgical Chair,of which the following is a spec1fication.

My present invention relates to a novel dental or surgical chair of thatclass characterized by hydraulic or other motive fluid lifting mechanismby means of which the seat or chair proper may be raised or lowered, and'thus properly positioned to accommodate the patient and the operator.

One object of the invention is to simplif and render more compact thechair supporting and lifting structure without sacrificing any of theadvantages which characterize Ehairs of more complicated and cumbersomeorm.

A further object of the invention is to construct the lifting mechanismirra manner which will permit it, together witliits various appurtenantdevices, to rotate with the chair so that the controlling means, as forinstance the pump-operating and the fluidfreleasing devices, as well asthe locking mechanism for securely holdin the chair after its adjustmenthas been e ected, will always remain in the same relative ositions withrespect to the chair seat to acilitate their actuation by the operatorirrespective of the position to which the chair may have been turned.

Another object of the invention is to improve the connections betweenthe elements of the lifting mechanism in order to insurefluid-tight-joints and to reduce the incidental friction totaminimum.

A still further object is to increase the stability of the structure bymountingthe various parts of the lifting mechanism, including thecontrolling valves, upon a single casting arranged for free rotationwithout the possibility of vibration and ca able of being easily andquickly displac or replaced to facilitate the adjustment or repair ofany part of the liftin mechanism or its appurtenant controllingevicesnother object of the invention is to arrange the standard or baseand lifting mechanism in such interfittin relation as will preclude thepossibility o lateral vibration or lost motion, and to provide novelmeans for limiting the elevation of the chair and for equalizlng thepressure areas of the piston or plunger elements to insure uniformmovement of the chair during the raismg and lowering thereof.

Subordinate to the several objects stated are various others which willappear during the illustrated structure.

' In the accompanying drawings :Figure 1 is a vertical sectional view ofthe chair supporting and lifting mechanism, a portion of the chair beingshown in elevation. Fig. 2 is a sectional view on the line 2-2 of Fig.3. Fig. 3 is a horizontal sectional view on the line 3--3 of Fig. 2.Fig. 4 is a sectional view designed to show particularly theconstruction and mounting of the operating devices for the releasevalve, pump and lock. Fig. 5 is a detail sectional View showing therelation of the pump, the release valve, the intermediate check valveand the connecting fluid passage. Fig. 6 is a detail sectional viewshowing the manner in which the pump is mounted in the head, and thefluid inlet. Fi 7 is a sectional view illustrating the fluid tight jointbetween the plunger and the extension tube; and Fig. 8 is an end view ofthe extension tube.

Like numerals designate corresponding parts in the several views of thedrawings.

The chair proper or seat, indicated by l, is supported by a standard 2,slidably received within a rotary head 3 carried by a fixed base 4,which latter rests upon the floor or other suitable support, and is ofsufficient weight to provide a solid foundation the course of thesucceeding description of -for the chair. The standard 2 is hollow andmay be of any desired form according to the range of movement required.That is to say, the standard 2 may be composed of a series of telescoing sections, or as shown in the illustrated farm of the invention, itmay be composed of a single cylinder of sutli cient diameter to insurethe necessary stability of the structure.

' At one side of the standard 2 is formed a longitudinal groove or way 5for the reception of a projection or key 6 extended inwardly from theconstricted upper endof the head 3, which forms a cylindrical hearing 7surrounding and closely fitting the standard. The standard 2 is thusfree to move vertically, independently of the head but necessarilyeffects the rotation of the head upon a vertical axis when the chair isturned. Below the bearing 7 the diameter of the head 3 is considerablyincreased to aca wall 9 upon which rests the lower end of the head 3,said end being preferably in the form of an annular casting 16 securedby suitable means, as for instance bolts 11,

to the other or upper member of the head.-

The upper portion of the base 4 from apoint a short distance above thecasting 10, is internally enlarged to define 'an oil s ace 12 incommunication with the interior 0 the head through openings 13, as shownin Fig. 1. The head and base thus combine to form a large internalchamber or reservoir for the reception ofthe oil or other motive fluiddesi ed to be employed for the operation of t e chair lifting mechanism.The annular casting 10 constituting the lower end of the head andfitting closely in the bot tom of the base is provided with adiametrical web 14, see Fig. 3, formed at its center with an internalscrew-threaded socket 15 for the reception of the lower threaded end ofa vertically disposed tube 16 constituting.

one of the telescoping members of the chair lifting mechanism. The tube16, rigidly-carried byv and designed to revolve with the head,constitutes in effect acylinder within which is designed to reciprocatea duplex piston comprising two telescoping members, the outer of which,indicated y 17, fits closely within the tube or cylinder 16, and

the inner of which, indicated by 18, fits within the tube or member 17as shown in Fig. 1. For the purpose of properly distinguishing theseseveral features of the chair lifting mechanism, the tube or cylinder 16will be referred to hereinafter'as the outer tube, the member 17 as theextension tube, and the member 18 as the plunger. 1

The upper end of the plunger 18 is closed as shown, and is receivedwithin a socket 19 preferablyformed in the lower end of a screw 20provided at the upperend of the standard tube for the attachment of thechair thereto. Motive fluid admitted to the lower end of the cylinder orouter tube 16 in the manner to be described, is designedto efl'ect,first, the elevation of the plunger 18 to lift the chair and tosubsequently effect the elevation of the plunger and extension tube inunison if the desired vertical adjustment of the chair exceeds the rangeof movement of the lunger.

The ower end of the extension tube 17' is closed by a disk 21 providedwith a series of openings 22 for the free passa e of the motive fluidand with an axia opening 23 which accommodates a vertical rod 24 rigidlysecured at its lower end to the web 14,

out the considerable and provided at its upper extremity with anenlargement 25 fitting within thehollow inner tube or plunger 18. Thisrod 24 performs several important functions. In the first place itconstitutes a centering device which assists in stifi'ening thestructure and in retaining the parts in their proper working positions.The enlargement 25 at the upper end of this rod constitutes a stopengaged by the disk 2.1 at the lower end of the extension tube 17 tolimit the upward movement of the latter. The third, and perhaps the mostimportant function of the rod 24, is to equalize the pressure areas ofthe extension .tube 17 and plunger 18 in order to insure the perfectlyuniform movement of the'chair ir'- respective of the particular elementor elements of the lifting mechanism moved under the impulse of themotive fluid.

At the upper end of the outer tube 16 is screwed 1a stufiing box 26having suitable packing 27 urged a ainst the outer face of the tube 17by a gand 28., This packing serves to effect a fluid-tight jointbetween-the outer tube 16 and the extension tube 17 withwhich hasheretofore resulted from the pro= vision of ackin at the. lower end ofthe extension tu e. is provided with a cap 29 in the form of a metaldisk of considerable diameter apertured to accommodate the plunger 18and having a threaded nipple 30 screwed into the tube 17,'as shown.There is no necessity for a fluid-tight connection at this point,however, for the reason that the inner tube or plunger 18 is providedwith anexternally threaded reduced lower end 31 surrounded by acking 32expanded against the interior sur ace of the tube 17 by a gland 33screwed upon the reduced end of the plunger, as shown in Fig. 7.

incidental friction T e upper end of the tube 17 The major diameter ofthe plunger 18 is somewhat less than the minor diameter of the extensiontube 17, the plunger being pro- .vided adjacent to its lower end'with anannular shoulder 34 arranged to contact withthe cap 29 to compel themovement of the It will, of course, be understood by those skilled inthe art that since the depression of the chair is efiected by therelease of the motive fluid, very little, if any, jar is likely to beoccasioned by the complete depression of the chair. III order, however,to avoidthe ossibilit of shock whenthe chair reaches its comp etelydepressed position, I prefer to mount a buffer spring 35 of an suitableform upon the. cap 29 and prefera ly encircling the plunger. When thechair comes to rest the cap 29 will have .a solid backing upon thestufiing box 26 at the upper end of the rigid outer tube or cylinder. 16and before the chair reaches its completely depressed position, theupper end of the. standard 2 will contact with the spring 35 and will becushioned by the latter in an obvious manner. It may also be observedthat this spring 35 assists somewhat in starting the chair when thelatter is elevated from its lowest position and while this assistance isperhaps inconsiderable, it is undoubtedly of some use in overcoming theinertia of vthe parts. i v 4 The standard 2, when entirely depressed, isdesigned to rest solidly upon the bottom wall 9 of the base, and inorder that this may be accomplished its lower end is notched orbifurcated, as indicated at 36, to accommodate the web 14 ofthe'head.

I have now completed the description of the chair supporting and liftingmechanism whereby the chair is permitted to turn or rotate upon avertical axis and is raised or lowered through the medium of a properlycontrolled motive fluid. It now remains to describe those appurtenantcontrollin devices whereby the motive fluid is force into the lower endof the outer tube or cylinder '16 under pressure to lift the chair andis permit-ted to escape when the lowering of the chair is desired, andalso the locking device by means of which the rotary part of the chairsupporting structure is securely retained after the chair has been"turned to the desired position. v

The casting 10, constituting the bottom of the head 3, while of generalannularshape, is formed at one side with an enlar ment 37 (see Fig. 3)to provide a meta body which supports the several valve mechanisms, andin which the fluid pamages are bored. Screwed into the upper side ofthis enlargement and preferably adjacentto one end thereof is a pumpcylinder 38 in communicat-ion with the oil chamber through an inletpassage or port 39. The passage 39 is enlarged at its lower end by arecess 40 in the bottom of the enlargement 37 and opening through thebottom and inner sides thereof, as shown in Fig. 6, said recess being.

guarded by a wire fabric netting constituting a strainer 41 whichpreventsthe passage of debris to the pump with the motive fluid.

The upper end of the passage 39: is flared to form a valve seat forthe-reception of a gravity-seated pump valve 42, which "operates in theusual manner to permit the-motive fluid to pass through the inletport'to the pump and to prevent back flow of the fluid through saidport. Within the pump is mounted to reciprocate a pump piston 43 havingan upwardly extending plston rod 44 connected to a retracting oppositeend of which is suitab y secured to a hook or other-projectionextending'inwardly from the wall of the head 3 (see Fig. 2)..

reason I provide 'flui -releasin(g ring 45, the

At the upper end of the piston rod 44 is formed a socket 46 for thereception of a stud 47projeeting from a crank arm 48 located at one endof a rock shaft 49 provided "with a bearing in and extending entirelythrough the wall of the head 3 (see Fig. 4). To the outer end of therock shaft 49 is securedin any suitable manner a pump lever 50 formedwith a foot-piece or pedal 51 to facilitate the depression of the pumplever by foot power. When the lever 50 is depressed the crank arm 48 isswung to depress the pump piston and the latter is then retracted by thespring 45 as the fobt of the operator is raised to repeat the operation.From the lower end of the pump cylinder 38, the motive fluid is forcedthrough a pas sage 52 to a check valve chamber '53 'within whichis-loosely retained a sphericalcheckvalve 54, which prevents thefluid-from passing back to the pump after it has once entered the valvechamber. The chamber 53 is preferably bored from the top ,of theenlargement 37 and is closed at its upper end by a screw cap 55, whichmay be easily removed tov permit access to the check valve. The passage53 opens into the bottom of the chamber 52 at a point below thevalveseat, and at a point somewhat above the valve the chamber 53 is incommunication with an an gular passage 56 formed conjointly in theenlargement 37, and in the web 14 of the casting 10 (see Fig. 3). Thepassage 56 opens into the outer tube or cylinder 16 throu h the bottomwall of the socket 15 and t us completes the communication between thepump cylinder and the outer tube or cylinder of the chair liftingmechanism. By the continued operation of the pump in themannerdescribed, the motive 'fluid is drawn into the pump cylinder and isforced under pressure to the chair lifting mechanism causing theelevation of the plunger 18 and the extensiontube 17 in a manner .wellunderstoodby those skilled in the art, for the pn ose of eifecting thevertical adjustment 0 the chair.

j It is evident that when it' is desired to lower the chair, the fluidmust be permitted to escape from the c linder 16.- For this I mechanismwhich may be readily operate to establish communication between thepassage 56 and the fluid reservoir. At'the juncture of its angularlyrelated branches, the passage 56 is in communcation with the shortescape port .57 extending upwardly and openin through the bottom of anannular recess ormed in 58 screwed upon the lower end of the releasevalve-casing 59 formed at its lower end with avalve chamber 60 intothelower extremity of which is screwed a detachable axially 'apertured'annulus 61. The annulus the upper side of the enlargement 37, and havingits .walls threaded to receive a collar 61 serves as a valve seat andalso as means for confining a spherical release valve 62 within thechamber 60 so that the entire release valve'mechanism may be easilyremoved from the head to facilitate cleaning or repair.

Extending upwardly from the chamber 60 is an axial bore 63 placed incommunication with the fluid reservoir through one or more dischargeports 64, the bore 63' being of such dimensions as will insure theproper closing of its lower end by the release valve (32' when thelatter is in the position indicated in Fig. 2 of the drawings. WVithinthe casing 59 above the valve 62 is mounted to reciprocate a valve stem65 having a reduced lower extremity 66 and an enlarged upper end 67, thelatter being accommodated in an enlargement 68 of the bore 63. The stem65 is normally urged upwardly by a helical spring 69 encircling the stemand bearing at one end against the enlargement 67 and at its oppositeend against the end wall of the bore enlar ement 68. The enlarged upperend ofttlie stem is provided with an annular recess 7 0 into whichextends a stop screw 71 designed to limit the mo vement'of the stem, andarranged to permit the removal thereof. fronf'tlie casing with facility.Normally the release valve and its stem will occupy the positions shownin Fig. 2, and the valve will thus prevent the escape of motive fluidthrough the discharge ports 64. If, however, it is desired to 'lower thechair, the depression of the stem 65 against the resistance of the fluidand ofthe spring 69 will move the release valve away from the lower endof the bore 63 and the fluid passing around the valve and into the borewill escape through the exhaust ports 64 and thus permit thechair togravitate to apartially or wholly depressed position, it being obviousthat the downward movement of the chair may be arrested at any point byreleasing the valve stem 65 and permitting the latter and the releasevalve to resume their normal positions to stop the further escape of themotive fluid from the cylinder 16. t

Since it is designed to have the various elements of the valve mechanisminclosed within the supporting structure of the chair, the stem 65 ofthe release valve is not exposed butis arranged to be depressed by arocker 7 2 disposed to engage the upper end of the stem 6:1 and secured'to the inner end of a rock shaft 7 3 extended through the wall of thehead, as' shown in Fig. 4, and having at its outer end a foot-operatedrelease valve lever 74. The rocker 7 2 is of angular'form and to one armthereof is secured one extremity of a retracting spring 75 secured atits lower endto the casting 10 (see Figs. 2 and 4). The end of therocker 72, which engages the valve stem, is p rovided with anfrictionally engage the base.

inclined or cam face 7 6 which, when the lever Tet is depressed, ridesupon the end of the stem 65 and forces the latter down to open therelease valve, the depression of the lever being limited by a stop 76 inthe form of an internal projection on the head 3 disposed to be engagedby the projection 77 on the rocker. As long as the foot of the operatorremains on the lever 74, the release valve will be held open and thechair will continue to descend. \Vhen the chair has reached its properposition, the lever 74 is released, the spring 75 retracts the rocker,

and the release valve and its stem are permitted to return to theirnormal positions to terminate the escape of the motive fluid and to stopthe descent of the chair.

Beside the pump level-50 and the release valve lever 74:, the head isequipped with a third lever designed to be actuated by the foot of theoperator. This third lever is a lock lever 78 which normally stands in asubstantially upright position, as shown in Fig. l, and is designed tobe pushed forward by the foot of the operator to effect the operation ofa locking device which serves to prevent further rotary movement of thechair after the latter has been properly positioned. The lock lever 78is mounted at the outer end of a screw 79 passed through a threadedopening in the wall of the head 3 and having its inner end' disposed tobear against the upper end of a locking lever 80 fulcrumed upon abracket 81 extending forwardly from the 'wall of the head. The lever 80is provided with an angular lower end '82 extended outwardly through oneof the openings 13in the head and disposed tobe urged into frictionalcontact with the wall of the base 4 to lock the head against movement.When the rotary supporting structure of the chair has been sufficientlyrotated, the operator by pushing upon the lock lever 78 imparts apartial rotation to the screw 79 feeding the latter in'a'n endwisedirection, and causin the lock lever 80 to berocked to that slightextent which is necessary to cause its angular end 82 to When it isdesired to rotate the chair, the lock lever 78 is moved slightly in theopposite direction to rotate the screw and relieve the pressure on thelocking lever inan obvious manner.

Since the operation of the several mechanismsdescribed has beenrecitedduring the. course of the preceding description, it is thought to beunnecessary 'to reiterate what has already been said in order to imparta clear idea of the invention: It should be distinctly understood,however,-that while the illustrated'embodlment of the invention theright toefi'ect such changes, modifications and variations of theillustrated structure as may come fairly within the scope of theprotection prayed. For instance, the standard 2 may be of sectional orother form, as already remarked, and likewise the piston element ofthechair lifting mechanism may comprise a plunger and an extension tube,as shown herein, or may be of single form, if preferred, it beingunderstood that in the latter event the extension tube 17 would beomitted and" that the plunger would be I properly proportioned to thecylinder or outer tube What I claim is 1. In a device of combinationwith a prising a hollow closely fit within 16.

seat, and a base comfixed member, and a hollow rotary member or headmounted therein, of fluid operated seat lifting mechanism, means forsupplying motive fluid to the mechanism, a horizontal pivot pierc ingthe wall of the rotary member or head, an oscillatory rocker connectedintermediate of its ends with the inner end of the pivot and provided atone end with a cam face, a spring connected with the other end of thereeker, a release valve casing mounted on the head, a release valve inthe easing, a valve stem extended above the easing and arranged in thepath of the cam face, and a release lever located exteriorly of the headand connected with the outer end of the said pivot.

.2. In a device of the character described, the combination with a seat,and a base comprising a hollow fixed member and a hollow rotary membermounted therein, of fluid operated seat lifting mechanism rising fromthe bottom of the head, means for supplying motive fluid to the liftingmechanism, a release valve casing mounted on the bottom of the rotarymember within the latter, a release valve in the casing, a valve stemextended above the casing, a substantially V-shaped rocker pivotallymounted within the head and having a cam face at one arm for engagingthe valve stem, and a spring connected with the other arm of the rocker.

, 3. In a device of the character described,

the combination with a seat, and a base comprising a hollbw fixed memberand a hollow rotary member mounted therein, of fluid operated seatlifting mechanism rising from the bottom of the head, means forsupplying motive fluid to'the lifting mechanism, a release valvecasinlg), mounted on the bottom of the rotary mem er within the latter,a re lease valve in the casing, a valve stem ex-- tended above thecasing, a substantially V-shaped' rockerpivotally mounted within thehead and having a cam face at one arm for enga ing the valve stem, aspring connected with the other arm of the rocker, and an operatinglever connected with the pivot of the rocker.

the class described, the v 4. In a device of the character described,the combination with a seat, and a base comprising a hollow fixed memberand a hollow rotary member mounted thereln, of fluid operated seatlifting mechanism, means for supplying motive fluid to theliftingmechanlsm, a release valve casing mounted on the bottom of therotary member within the latter, a release valve in the casing, a valvestem extended above the casing, a substantially V-shaped rockerpivotally mounted within the rotary member and having one of its armsarranged to engage the valve stem, the other arm of the rocker beingprovided with a projection, and a stop arranged in thepath of theprojection for limiting the movement of the rocker.

5. In a deviceof the character described, the combination with a seat,and a base comprising a hollow fixed member and a hollow rotary membermounted therein, of fluid operated seat lifting mechanism, means forsupplying motive fluid to the lifting mechanism,

a release valve casing mounted on the bottom of the rotary member withinthe latter, a release valve in the casing, a valve stem extended abovethe casing, a substantially V-shaped rocker pivotally mounted within therotary member and having one of its arms arranged to engage the valvestem, the other arm of the rocker being provlded wlth a projection, astop arranged 1n the path of the projection for limiting the movement ofthe rocker, a spring connected wan the arm havin the projection, and anexterior operating ever connected with the pivot of the rocker.

6. In a device of the class described, the combination with a seat, anda base including a rotary member, of'seat lifting mechamsm carried bysaid rotary member, a pump for supplying fluid to the l fting mechanism,sald pump includinga cylinder, a piston therein, and a piston rod havinga socket at its upper end, a horizontal rock shaft having a bearing inthe wall of the rotary base member, a crank mounted at the inner end ofthe rock shaft and provided with a horizontally projecting stud arrangedto engage the socket at the upper end of the piston rod, a pump lever atthe outer end of the rock shaft, and means for retracting the piston.

7. In a device of the class described, the combination with a seat, anda base comprising a fixed member, and a rotary member having a threadedopening and provlded at its inner face with a bracket, of seat liftingmechanism carried by the rotary member, and a locking device forretaining the rotary member in its adjustment, said locking deviceincludin an upright lever pivoted to the bracket and extending above andbelow the same, the lower end of the lever being provided with anengaging portion pro e cting through the wall of the rotary member andengaging the fixed member, and a screw mounted in the threaded 0 eningof the rotary member and arrang to bear against the upper portion of thelever.

8. In a device of the character described, the combination with a seat,a base, and fluid operated chair lifting mechanism, of release valvemechanism including a release valve casing formed in a single piece andprovided at its lower end with a valve chamber and having. a boreextending upward from the chamber and enlarged at the upper portion ofthe casing, said casing being also provided with a port extendinglaterally from the bore at a point between the chamber and the saidenlarged upper portion, a valve located within the chamber, a valve stemoperating within the bore and extending from the valve chamber to theenlarged u per portion of the bore, a spring housed wlthin therupperportion of the bore and engaging the stem of the valve, and means forengaging the'valve stem to operate the valve.

valve stem having its upper end enlarged and its lower end reduced andmounted to reciprocate within the casing, a spring enclrclmg the valvestemjand bearing at one' end against the enlargement thereof, and a stopscrew carried by the casing and engaging the valve stem to limit themovement thereof. 7

.In testimony, that I claim the foregoing as my own, I have heretoafiixed my slgnature in the presence oi two witnesses;

GUSTAV 'HOLT Z.

' Witnesses:

A. L. RHODES, C. H. BROWN.

